NOW FOR SALE

1.

Shiny Eyes SE UL EL34-6SL7 tube amplifier

Despite the fact that my love stays with DHTs, I’ve designed and built this amp to fill a gap that I thought it was worth the effort: making an amp in one enclosure, small enough but able to put out more power than a 45 or a 4P1L could do. I’ve also wanted to compare the sound with the 300B amp I was building at the same time.

It all started while I was trying to figure out what amp to build with my last pair of James6123HS. I breadboard the EL34 and tried many drivers and configurations. I’ve ended up liking the 6SL7 paralleled and using a small amount of global NFB, just enough to bring the distortions down, while widening the frequency response and increasing the damping factor.

This amp measure good as well as sounds very nice. It gives a max 8W at 1.7% ( 0.58% at 1W, 1% at 3W and 1.25% at 5W). The input sensitivity is 1Vrms for 5W output. The frequency response is 10Hz-40kHz @ +0.25dB for 3W output. The damping factor is about 7.

As expected this amp has a predominant 2nd harmonic and the sound is very pleasant. Dear reader, please remember this is still a low power, single ended amp and will do the right thing if it is used with the right type of speaker ( easy to drive, preferably full range) and music.

I am very pleased with the sound of this amp and considering the cost of tube replacement, I am kindly recommend it for ever is looking for a decent cost SE tube amp that will sound as close to a DHT as possible.

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13 thoughts on “Stuff For Sale and Feedback”

I can heartily recommend anything that Radu builds. I purchased a 301A DHT tube preamp from him through EBay last year. It is built like a tank and very carefully thought out. Adds that wonderful DHT goodness to my system which has a Pass Labs solid state amp and single driver speakers. Radu even customized the preamp for me in order to drop the gain a bit.

It is hard to believe that he makes money on these builds. He seems to be doing it for love of the endeavor! Highly recommended.

I bought a 4P1L and F4 combo through eBay Radu. It sounds excellent. After that, I asked Radu to built a 26/01A tube preamp for me. He also fixed the hum issue for my amplifiers. This is the best experience I have ever had in my 20 audiophile years. The 26/01A performs just like a 10k and above preamp. The sound opens up just like a real live concert.

Radu is knowledgeable and considerate. Through multiple projects with him, he is always keeping customer first in his mind and makes you extremely happy and surprise by going extra miles.

I had built preamplifiers with 4P1L tube by myself. After 6 months of tuning it, I found that this tube is difficult for me despite its great sound. Finally, I had given up.

But its sound was awesome, I googled for 4P1L preamp at times. And fortunately, I found Radu’s website and I purchased 4P1L preamp from Radu.

In short, it’s really awesome.
3D-stage, natural tone, and transparency. I can hear what I wanted. And absolutely no noise.
Its bass is not huge, but it grips.
And for the chassis, it’s better than it looks in photograph.

I can recommend it to whoever loves DHT’s sound. You cannot know its sound before you hear it.

I would highly recommend any of Radu’s build projects. Radu last year built me a Statement
101b,26 tube preamplifier. OUTSTANDING,,in finish as well as build. Hand picked top of the Line parts quality and sonics several categories above the commercial priced companies.
Which you pay huge50% markups. Here that money goes directly into the top quality Lundahl transformers, powder coated,pinstriped top and front panels and writting of my choosing.
Custom Precision Electronics.Myself a 35 years Audiophile, this is perfect for the quality
that I require. Since then Radu has built me a Pass Labs Dual Mono First Watt F-6 amplifier .
I could not recommend any higher any Audio designer, Technician ,PJ Letteri.

Hello Daniel,
I’ve sent you an email. I’m no longer building one enclosure DHT preamps. DHTs are very sensitive and capture hum from a nearby transformer or tube rectifier..
Keeping the AC away from the main preamp enclosure is a must in order to have a very low noise DHT preamp.
Cheers,
Radu

I’d be interested in using a 4p1l design either for preamp/buffer duty or for ‘powering’ my compression drivers (active horn system). I thought about a single stage (one single 4p1l) per channel, no driver. Gain is not an issue because the compression drivers’ sensitivities are markedly above 110dB and I’m listening in the near field.

Questions:
-Would the noise (DHT design) be a problem in my setting?
-Would it be possible to use this amp indifferently as preamp or as amp? Note that the impedance of the compression drivers is relatively high (32 ohm).

Hi Marc,
4P1L is a very nice tone tube. However, it is quite microphonic at lower signal levels. Using as a final stage in a power amp, the signal levels are high ( up to 100Vrms) and the microphonics are manageable, The tube goes through a warm up period of 10-30 minutes where one will hear pings. After reaching a steady thermal state there should be no noises besides the ones created by airbourne waves ( microphonics).
Your driver is pretty sensitive. Lets assume you only need 0.25W average power to create a good listening sound pressure level. This translates to 2.82Vrms at the speaker level. I would use LL2765/30mA in 12:1 configuration. The 4P1L will average an 8x gain loaded to the LL2765. Therefore, with only one stage you will need about 4.3Vrms input to get 0.25W on your driver.

Radu designed and built for me a pair of amazing mono-block amps 26>>>46>>>50
All I can say here is that they are flawlessly working and successfully competing with more expensive products. He is a dedicated professional and a fair and honest person. Highly recommended !!

Thank you Radu for the finest 300B amp. I’ve ever owned or hope to own! Its build quality, appearance and performance are well beyond its price point; in fact, imho it would be hard to improve upon at any price. Glorious sound, a wonderful match for open baffle speakers and cdp source. This one is a keeper for sure. And it was a great pleasure to meet you, Radu. You are a someone of great integrity and incredible knowledge in your chosen field. Hope to call upon you again for a preamp to go along with it.
Aloha nui loa!
Dean